US20230114916A1 - Positive electrode piece and secondary battery including same - Google Patents

Positive electrode piece and secondary battery including same Download PDF

Info

Publication number
US20230114916A1
US20230114916A1 US18/065,616 US202218065616A US2023114916A1 US 20230114916 A1 US20230114916 A1 US 20230114916A1 US 202218065616 A US202218065616 A US 202218065616A US 2023114916 A1 US2023114916 A1 US 2023114916A1
Authority
US
United States
Prior art keywords
positive electrode
formula
electrode piece
polymer
chain segment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
US18/065,616
Inventor
Weichao TANG
Suli LI
Wei Zhao
Hao Yuan
Chunyang Liu
Junyi Li
Yanming Xu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhuhai Cosmx Battery Co Ltd
Original Assignee
Zhuhai Cosmx Battery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zhuhai Cosmx Battery Co Ltd filed Critical Zhuhai Cosmx Battery Co Ltd
Assigned to ZHUHAI COSMX BATTERY CO., LTD. reassignment ZHUHAI COSMX BATTERY CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LI, JUNYI, LI, Suli, LIU, CHUNYANG, TANG, Weichao, XU, Yanming, YUAN, HAO, ZHAO, WEI
Publication of US20230114916A1 publication Critical patent/US20230114916A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/137—Electrodes based on electro-active polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0065—Solid electrolytes
    • H01M2300/0082—Organic polymers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present disclosure relates to the technical field of secondary batteries, in particular to a positive electrode piece and a secondary battery including the positive electrode piece.
  • Lithium-ion battery has advantages, such as long cycling life, high energy density, green and environmental friendly, and has been applied in energy storage field, power field, and digital field. With the urgent demand for high energy density batteries in the market, the traditional lithium-ion battery system is increasingly difficult to meet the market demand.
  • the lithium-ion battery is mainly composed of a positive electrode, a negative electrode, a separator and an electrolyte.
  • the electrolyte is mainly composed of an organic solvent.
  • the battery has safety problems such as leakage, fire, explosion, etc. Solid state batteries are expected to fundamentally improve the safety performance of the lithium-ion battery, and have received extensive attention at home and abroad.
  • Solid state battery is a strong competitor for the next generation of energy storage battery with high energy density.
  • an all-solid electrolyte still faces a problem of excessive interfacial contact impedance, especially on the positive electrode side, which greatly restricts the application of the all-solid electrolyte.
  • a solid electrolyte mainly includes sulfide electrolyte, oxide electrolyte, polymer electrolyte, hydride electrolyte, etc., where sulfide electrolyte has the disadvantages of high interfacial impedance, unstable performance, etc., the oxide electrolyte has the disadvantages of low conductivity, poor interfacial contact, etc., the hydride electrolyte has the disadvantages of unstable performance, flammability and explosion, etc., and the polymer electrolyte has characteristics of good processability and low room-temperature conductivity.
  • the present disclosure aims to provide a positive electrode piece and a secondary battery including the positive electrode piece.
  • the positive electrode piece of a conventional all-solid state battery mainly includes a positive-electrode active material, a conductive agent, a binder and a solid electrolyte, where the positive-electrode active material, conductive agent, binder and solid electrolyte are uniformly mixed, and are coated on a surface of a current collector, and then are dried and cut to obtain the positive electrode piece for the solid state battery, and the positive electrode piece, the solid electrolyte and a negative electrode piece are laminated, to obtain a solid state lithium-ion battery.
  • a positive electrode piece including a positive-electrode current collector and a positive-electrode active material layer coated on one or both surfaces of the positive-electrode current collector, where the positive-electrode active material layer includes a positive-electrode active material, a conductive agent and a polymer electrolyte, where the polymer electrolyte includes a polymer and a lithium salt, and the polymer includes a repeating unit as shown in Formula 1 below:
  • R 1 is selected from H or C 1-6 alkyl group
  • R 2 is selected from a connecting group
  • R 3 is selected from a capping group
  • M is selected from polyphenylene oxide chain segment, polyethylene glycol chain segment, polyethylene dithiol chain segment, polycarbonate chain segment, polypropylene glycol chain segment or polysiloxane chain segment.
  • R 1 is selected from H or C 1-3 alkyl group
  • R 2 is a connecting group formed by a reaction of hydroxyl group in
  • R 3 and R 3 ′ are the same or different, and are each independently selected from H, OH, COOH and NH 2 and cannot be H at the same time.
  • the polyphenylene oxide chain segment has a repeating unit shown in Formula 2:
  • R 4 is selected from H or C 1-6 alkyl group, and m is an integer between 0-4.
  • R 4 is selected from H or C 1-3 alkyl group, and m is an integer between 0-2;
  • polyethylene glycol chain segment has a repeating unit shown in Formula 3:
  • polypropylene glycol chain segment has a repeating unit shown in Formula 4:
  • polyethylene dithiol chain segment has a repeating unit shown in Formula 5:
  • polycarbonate chain segment has a repeating unit shown in Formula 6:
  • the polymer is selected from at least one of polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polyethylene dithiol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.
  • a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
  • R 1 , R 2 , R 3 and M are defined as above.
  • the compound shown in Formula 8 is selected from at least one of polyphenylene oxide acrylate, polyethylene glycol methyl methacrylate, polycarbonate acrylate, polypropylene glycol methacrylate, poly(lithium-sulfonate) methacrylate, and polysiloxane methyl methacrylate.
  • the positive-electrode active material layer includes the following components in mass percentage of content: 70-95 wt % of the positive-electrode active material, 2-15 wt % of the conductive agent, 3 -28 wt % of the above-mentioned polymer electrolyte and 0-10 wt % of a binder.
  • a molar ratio of other elements except carbon and hydrogen in the polymer to lithium element in the lithium salt is 5:1-25:1, such as 5:1, 10:1, 15:1, 20:1, 25:1, where the other elements except carbon and hydrogen can be, for example, oxygen, sulfur or silicon element.
  • a porosity of the positive electrode piece is 0%-5%; and/or an elongation ratio of the positive-electrode active material layer in the positive electrode piece is 5%-500%.
  • the present disclosure further provides a solid state battery, and the solid state battery includes the positive electrode piece described above.
  • the present disclosure provides a positive electrode piece and a secondary battery including the positive electrode piece.
  • the present disclosure selects a type of polymer electrolyte prepared from a polymer different from that in the prior art as the solid electrolyte in the positive electrode piece, the solid electrolyte have both a bonding function and a lithium conduction function, can replace a binder and a solid electrolyte in an existing electrode piece, can effectively improve and enhance transmission performance of the lithium ion, and reduce the internal resistance of the battery.
  • the positive electrode piece including the solid electrolyte has low porosity, below about 5%, which greatly reduces the voids and holes in the positive electrode piece, increases the content of the positive-electrode active material in unit volume, improves the transmission of lithium ions and electrons, and effectively improves the energy density, cycling performance and rate performance of the battery.
  • the positive electrode piece including the solid electrolyte can be used in a battery system with high energy density, and broadens application field thereof.
  • the present disclosure provides a positive electrode piece, the positive electrode piece includes a positive-electrode current collector and a positive-electrode active material layer coated on one or both surfaces of the positive-electrode current collector, the positive-electrode active material layer includes a positive-electrode active material, a conductive agent and a polymer electrolyte, where the polymer electrolyte includes a polymer and a lithium salt, and the polymer includes a repeating unit as shown in Formula 1 below:
  • R 1 is selected from H or C 1-6 alkyl group
  • R 2 is selected from a connecting group
  • R 3 is selected from a capping group
  • M is selected from polyphenylene oxide chain segment, polyethylene glycol chain segment, polyethylene dithiol chain segment , polycarbonate chain segment, polypropylene glycol chain segment or polysiloxane chain segment.
  • R 1 is selected from H or C 1-3 alkyl group, for example, R 1 is selected from H or methyl.
  • R 2 is a connecting group formed by a reaction of hydroxyl group in
  • R 2 is a residue of R 3 ′, where R 3 ′ is a capping group of M.
  • R 3 and R 3 ′ are the same or different, and are each independently selected from H, OH, COOH, NH 2 and other capping group that can react with hydroxyl group, and cannot be H at the same time.
  • the polyphenylene oxide chain segment has a repeating unit shown in Formula 2:
  • R 4 is selected from H or C 1-6 alkyl group, and m is an integer between 0-4.
  • R 4 is selected from H or C 1-3 alkyl group, and m is an integer between 0-2; specifically, the polyphenylene oxide chain segment has a repeating unit shown in Formula 2′:
  • the polyethylene glycol chain segment has a repeating unit shown in Formula 3:
  • the polypropylene glycol chain segment has a repeating unit shown in Formula 4:
  • the polyethylene dithiol chain segment has a repeating unit shown in Formula 5:
  • the polycarbonate chain segment has a repeating unit shown in Formula 6:
  • the polysiloxane chain segment has a repeating unit shown in Formula 7:
  • a number average molecular weight of M is 200-40000.
  • the polymer is selected from at least one of polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polyethylene dithiol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.
  • a number average molecular weight of the polymer is 1000-300000, preferably 10000-200000.
  • a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
  • R 1 , R 2 , R 3 and M are defined as above.
  • the compound shown in Formula 8 is selected from at least one of polyphenylene oxide acrylate, polyethylene glycol methyl methacrylate, polycarbonate acrylate, polypropylene glycol methacrylate, poly(lithium-sulfonate) methacrylate, and polysiloxane methyl methacrylate.
  • the positive-electrode active material layer includes the following components in mass percentage of content: 70-95 wt % of positive-electrode active material, 2-15 wt % of conductive agent, 3-28 wt % of the above-mentioned polymer electrolyte and 0-10 wt % of binder.
  • a molar ratio of other elements except carbon and hydrogen in the polymer to lithium element in the lithium salt is 5:1-25:1, such as 5:1, 10:1, 15:1, 20:1, or 25:1, where the other elements except carbon and hydrogen can be, for example, oxygen, sulfur or silicon element.
  • a content of the positive-electrode active material in mass percentage is 70 wt %, 71 wt %, 72 wt %, 73 wt %, 74 wt %, 75 wt %, 76 wt %, 77 wt %, 78 wt %, 79 wt %, 80 wt %, 81 wt %, 82 wt %, 83 wt %, 84 wt %, 85 wt %, 86 wt %, 87 wt %, 88 wt %, 89 wt %, 90 wt %, 91 wt %, 92 wt %, 93 wt %, 94 wt %, or 95 wt %.
  • a content of the conductive agent in mass percentage is 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, or 15 wt %.
  • a content of the polymer electrolyte in mass percentage is 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, 15 wt %, 16 wt %, 17 wt %, 18 wt %, 19 wt %, 20 wt %, 21 wt %, 22 wt %, 23 wt %, 24 wt %, 25 wt %, 26 wt %, 27 wt %, or 28 wt %.
  • a content of the binder in mass percentage is 0 wt %, 1 wt %, 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, or 10 wt %.
  • the positive-electrode active material is selected from one of or a combination of more of ferrous lithium phosphate (LiFePO 4 ), lithium cobaltate (LiCoO 2 ), lithium nickel cobalt manganate (Li z Ni x Co y Mn 1-x-y O 2 , where 0.95 ⁇ z ⁇ 1.05, x>0, y>0, 0 ⁇ x+y ⁇ 1), lithium manganate (LiMnO 2 ), lithium nickel cobalt aluminate (Li z Ni x Co y Al 1-x-y O 2 , where 0.95 ⁇ z ⁇ 1.05, x>0, y>0, 0.8 ⁇ x+y ⁇ 1), lithium nickel cobalt manganese aluminate (Li z Ni x Co y Mn w Al 1-x-y-w O 2 , where 0.95 ⁇ z ⁇ 1.05, x>0, y>0, w>0, 0.8 ⁇ x+y+w ⁇ 1),
  • the lithium salt is selected from one of lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium bisoxalate borate (LiBOB), lithium difluorooxalate borate (LiDFOB), lithium bis(difluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulphonyl)imide (LiTFSI), lithium trifluoromethylsulfonate (LiCF 3 SO 3 ), lithium bismalonate borate (LiBMB), lithium malonate oxalate borate (LiMOB), lithium hexafluoroantimonate (LiSbF 6 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium 4,5 -dicyano
  • the conductive agent is selected from one or more of conductive carbon black, Ketjen black, conductive fiber, conductive polymer, acetylene black, carbon nanotube, graphene, flake graphite, conductive oxide and metal particle.
  • the binder is selected from at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinylidene fluoride hexafluoropropylene and poly(lithium-acrylate) (PAALi).
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PAALi poly(lithium-acrylate)
  • the positive electrode piece is used in a solid state battery (such as an all-solid state battery).
  • a porosity of the positive electrode piece is 0%-5%.
  • an elongation ratio of the positive-electrode active material layer in the positive electrode piece is 5%-500%.
  • a surface density of the positive electrode piece is 5-30 mg/cm 2 .
  • the present disclosure also provides a preparation method of the positive electrode piece, which includes the following steps: uniformly mixing a solvent, a positive-electrode active material, a conductive agent, a polymer monomer shown in Formula 8, an initiator and a lithium salt to prepare a positive electrode slurry; coating the positive electrode slurry on a surface of a positive-electrode current collector, and drying and hot pressing, to obtain the positive electrode piece.
  • the positive electrode slurry includes 200-1000 parts of the solvent, 70-95 parts of the positive-electrode active material, 2-15 parts of the conductive agent, 3-28 parts of the polymer monomer shown in Formula 8, the initiator and the lithium salt, and 0-10 parts of a binder; where a molar ratio of other elements except carbon and hydrogen in the polymer monomer shown in Formula 8 to lithium element in the lithium salt is 5:1-25:1, and an addition amount of the initiator is 0.05-1 wt % of the mass of the polymer monomer shown in Formula 8.
  • the initiator can be one or more of azodiisobutyronitrile, azodiisoheptonitrile, dimethyl azodiisobutyrate, benzoyl peroxide, tert-butyl peroxybenzoate, 4-(N,N-dimethylamino)ethyl benzoate, methyl o-benzoylbenzoate, and the like.
  • the solvent is selected from at least one of N-methylpyrrolidone, acetonitrile, hydrofluoroether, acetone, tetrahydrofuran, dichloromethane, pyridine, xylene and toluene.
  • the positive electrode slurry is preferably sieved positive electrode slurry, such as through a 200-mesh sieve.
  • a temperature of the drying is 60° C.-120° C., and time of the drying is 6-36 hours; further preferably, the drying is carried out under vacuum.
  • a temperature of the hot pressing is 50° C.-90° C., and time of the hot pressing is 5-60 minutes.
  • the positive-electrode active material, the conductive agent, optionally the binder, the polymer monomer, the initiator and the lithium salt are dissolved in the solvent, uniformly mixed, and coated on the surface of the current collector, and then is dried, hot pressed, and then the positive electrode piece of the present disclosure is obtained.
  • the polymer monomer due to its small molecular weight and short polymer chain segment, can be fully mixed with the positive-electrode active material, the conductive agent, optionally the binder and the lithium salt.
  • the solvent is removed, a highly efficient lithium conductive network has been formed in the positive-electrode active material layer, and is subjected to hot pressing under vacuum.
  • the hot pressing is to initiate thermal polymerization of the polymer monomer, the polymer monomer is viscous liquid, semi-solid or solid at room temperature, and the polymer monomer becomes a flowable liquid at high temperature, can fully immerse into the internal voids of the electrode piece, and conducts thermal initiation polymerization in the voids, where the thermal initiation polymerization process (time and temperature) is adjustable to ensure the lithium conductivity of the positive electrode piece; on the other hand, the hot pressing polymer process under vacuum is adopted, the vacuum can remove air between particles inside the electrode piece, and the hot pressing can ensure compaction of the electrode piece, to be closer to the practical application.
  • the above processes are mainly to ensure performance of the electrode piece with low void ratio, high lithium conductivity and high conductivity.
  • the present disclosure also provides a solid state battery, and the solid state battery includes the positive electrode piece described above.
  • the present disclosure also provides an electrical device, and the electrical device includes the positive electrode piece described above.
  • the electrical device is a digital appliance, a power tool, an energy storage device, an unmanned aerial vehicle, a household appliance, an energy storage product, an electric vehicle, an electric tool, and the like.
  • lithium cobaltate as positive-electrode active material
  • 3 g of polyphenylene oxide acrylate 0.33 g of LiBF 4 , 0.67 g of LiTFSI, 1 g of polyvinylidene fluoride (PVDF) as binder, 1 g of carbon black as conductive agent, 1 g of carbon nanotube as conductive agent, 0.01 g of azodiisobutyronitrile were mixed, 1000 g of N-methylpyrrolidone (NMP) was added, and stirred under the action of a vacuum mixer until the mixed system becomes a uniform flowable positive electrode slurry; the positive electrode slurry was applied evenly on an aluminum foil with a thickness of 10 ⁇ m; after drying at 60° C. for 36 hours, the electrode piece was obtained after vacuumization treatment, and the electrode piece was hot pressed at 50° C. for 60 minutes, and then cut to obtain the positive electrode piece.
  • NMP N-methylpyrrolidone
  • the positive electrode piece, the solid electrolyte film and the negative electrode piece obtained above were laminated to prepare a solid lithium-ion battery cell, which was welded and encapsulated, to obtain the lithium-ion battery.
  • a specific process may refer to Example 1, where a main difference is that in the Comparative example 1-1, polyphenylene oxide is used to replace the polyphenylene oxide acrylate in Example 1; and other conditions are consistent with Example 1.
  • a specific process may refer to Example 1, where a main difference is that a mixture of polyphenylene oxide and polyacrylate with the same mass as the polyphenylene oxide acrylate monomer is used in the Comparative example 1-2 to replace the polyphenylene oxide acrylate in Example 1, where a mass ratio of polyphenylene oxide and polyacrylate is a molecular weight ratio of polyphenylene oxide to acrylate in the polyphenylene oxide acrylate monomer; and other conditions are consistent with Example 1.
  • Example 1 Specific processes may refer to Example 1, where main differences are the process conditions, addition amounts of respective components, and types of respective component materials. See Table 1 and Table 2 for details. Among them, Examples 1-6 in Table 1 further include 0.01 g of initiators, all of which are azodiisobutyronitrile. In the comparative examples in Table 2 where two polymers are added, addition amounts of the two polymers are a molecular weight ratio of the polymer chain segments to the poly(meth)acrylate in the polymer monomers added in corresponding examples. See description of the above Comparative example 1-2 for details.
  • Example 1 1000 92 2 3 2 1 60 36 50 60 Comparative 1000 92 2 3 2 1 60 36 50 60 example 1-1 Comparative 1000 92 2 3 2 1 60 36 50 60 example 1-2
  • Example 2 600 75 8 12 5 0 90 24 65 10 Comparative 600 75 8 12 5 0 90 24 65 10 example 2-1 Comparative 600 75 8 12 5 0 90 24 65 10 example 2-2
  • Example 3 400 70 5 12 3 10 120 6 80 15 Comparative 400 70 5 12 3 10 120 6 80 15 example 3-1 Comparative 400 70 5 12 3 10 120 6 80 15 example 3-2
  • Example 4 500 90 3 6 1 0 110 16 90 5 Comparative 500 90 3 6 1 0 110 16 90 5 Comparative 500 90 3 6 1 0 110 16 90 5 example 4-1 Comparative 500 90 3 6 1 0 110 16 90 5 example 4-2
  • alternating current impedance for lithium-ion battery is tested in 100 KHz-0.1 mHz range at 60° C., using Metrohm PGSTAT302N chemical workstation.
  • Test method for porosity of electrode piece porosity of electrode piece is tested using mercury porosimeter with model 9610 under AutoPore V series, where a certain electrode piece is taken and placed in a dilatometer, which is coated with high-pressure sealing oil, covered and sealed with threads, and then placed in a high-pressure system to test the porosity of electrode piece under high pressure.
  • Test method for elongation ratio of electrode piece positive electrode slurry is coated on a smooth and flat surface, dried and hot pressed, to obtain a slurry-coated layer, which is prepared to 60 mm*20 mm*1 mm (length*width*thickness) sample, and a tensile test is conducted on the sample on hydraulic universal material testing machine with model GH-969C.
  • Test method for battery cycling performance a charge and discharge cycling test for a lithium-ion battery is conducted on a battery (from LANHE) charge and discharge test cabinet, with the test conditions being 60° C., 0.3 C/0.3 C charge and discharge, and cycling times when battery capacity retention rate drops to 80% are investigated.
  • Test method for battery cycling rate performance a charge and discharge cycling test for a lithium-ion battery is conducted on a battery (from LANHE) charge and discharge test cabinet, with the test conditions being 60° C., and a process at 0.3 C/0.3 C (5 cycles) ⁇ 0.5 C/0.5 C (5 cycles) ⁇ 1 C/1 C (5 cycles) ⁇ 2 C/2 C (5 cycles) ⁇ 0.3 C/0.3 C (5 cycles) is carried out.
  • the porosity test results show that: in the examples, the positive electrode pieces prepared by using the compound shown in Formula 8, has low porosity; in the comparative examples, formed polymers adopted cannot achieve the effect of low porosity.
  • the compound shown in Formula 8 adopted in the present disclosure is a polymer monomer, which is liquid under heat condition, and can fully contact with particles, enter voids between particles, and achieve in-situ polymerization in the voids, that is, preparing a positive electrode piece with low porosity.
  • the test results of elongation ratio show that: by comparing the elongation ratios of the positive-electrode active material layers in Examples 1-6, it can be seen that the elongation ratio of the positive-electrode active material layer is related to the amount of polymer monomer added, and the more the polymer monomer added, the better the elongation ratio; by comparing the examples with the comparative examples, the compound shown in Formula 8 in the present disclosure has obvious comb-like polymer function, where the main chain is carbon-carbon bond, and the branch chain is comb like, and the compound can effectively combine with particle materials in the positive electrode piece, has good high elasticity state, and has good elongation ratio.
  • the battery internal resistance test results show that: the compound shown in Formula 8 adopted in the examples of the present disclosure can effectively bond particles in the positive electrode piece together, and meanwhile, the polymer has a comb-like structure, and the branch chain can conduct lithium, so the positive electrode pieces prepared in Examples 1-6 have a low internal resistance. However, there is a high porosity in the comparative examples and the polyacrylate does not conduct lithium, so the positive electrode pieces prepared in the comparative examples have a high internal resistance.
  • the positive electrode pieces of the present disclosure have a low porosity and a small internal resistance, which makes that the batteries prepared have an advantage in cycling performance; however, the positive electrode pieces in the comparative examples have a high porosity and a high internal resistance, leading to a significant reduction of the effective cycling times of the batteries.
  • the positive electrode pieces of the present disclosure have a low porosity and a small internal resistance, and the lithium ions have good lithium conductive channels in the positive electrode pieces, which makes that the prepared lithium-ion batteries have good rate performance and good application value.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Dispersion Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

A positive electrode piece and a secondary battery including the same. By selecting a type of polymer electrolyte prepared from a polymer different from that in the prior art as the solid electrolyte in the positive electrode piece, the solid electrolyte have both a bonding function and a lithium conduction function, may replace a binder and a solid electrolytes in an existing electrode piece, can effectively improve and enhance the lithium ion transmission performance, and reduce the internal resistance of the battery. Meanwhile, the positive electrode piece including the solid electrolyte has a low porosity, below about 5%, which greatly reduces voids and holes in the positive electrode piece, increases the content of the positive-electrode active material in unit volume, improves the transmission of lithium ions and electrons, and effectively improves the energy density, cycling performance and rate performance of the battery.

Description

    CROSS-REFERENCE TO RELATED APPLICATION
  • This application is a continuation of International Application No. PCT/CN2021/094181, filed on May 17, 2021, which claims priority to Chinese Patent Application No. 202010606376.2, filed on Jun. 29, 2020, both of which are hereby incorporated by reference in their entireties.
    • TECHNICAL FIELD
  • The present disclosure relates to the technical field of secondary batteries, in particular to a positive electrode piece and a secondary battery including the positive electrode piece.
    • BACKGROUND
  • Lithium-ion battery has advantages, such as long cycling life, high energy density, green and environmental friendly, and has been applied in energy storage field, power field, and digital field. With the urgent demand for high energy density batteries in the market, the traditional lithium-ion battery system is increasingly difficult to meet the market demand. The lithium-ion battery is mainly composed of a positive electrode, a negative electrode, a separator and an electrolyte. The electrolyte is mainly composed of an organic solvent. In a battery system with high energy density, the battery has safety problems such as leakage, fire, explosion, etc. Solid state batteries are expected to fundamentally improve the safety performance of the lithium-ion battery, and have received extensive attention at home and abroad.
  • Solid state battery is a strong competitor for the next generation of energy storage battery with high energy density. However, an all-solid electrolyte still faces a problem of excessive interfacial contact impedance, especially on the positive electrode side, which greatly restricts the application of the all-solid electrolyte. At present, a solid electrolyte mainly includes sulfide electrolyte, oxide electrolyte, polymer electrolyte, hydride electrolyte, etc., where sulfide electrolyte has the disadvantages of high interfacial impedance, unstable performance, etc., the oxide electrolyte has the disadvantages of low conductivity, poor interfacial contact, etc., the hydride electrolyte has the disadvantages of unstable performance, flammability and explosion, etc., and the polymer electrolyte has characteristics of good processability and low room-temperature conductivity.
  • At the same time, there are some problems in the positive electrode of the solid state battery, such as poor interfacial contact, high porosity, and oxidative decomposition of polymer electrolyte, which directly affect the cycling performance of the solid state battery.
    • SUMMARY
  • In order to overcome deficiencies of the prior art, the present disclosure aims to provide a positive electrode piece and a secondary battery including the positive electrode piece.
  • It was found through research that the positive electrode piece of a conventional all-solid state battery mainly includes a positive-electrode active material, a conductive agent, a binder and a solid electrolyte, where the positive-electrode active material, conductive agent, binder and solid electrolyte are uniformly mixed, and are coated on a surface of a current collector, and then are dried and cut to obtain the positive electrode piece for the solid state battery, and the positive electrode piece, the solid electrolyte and a negative electrode piece are laminated, to obtain a solid state lithium-ion battery. During charging and discharging process of a conventional all-solid state battery, there are problems such as poor interfacial contact between an electrode piece and a solid electrolyte, and high porosity on an electrode piece surface, which greatly affects the cycling performance of the solid state battery.
  • An object of the present disclosure is realized by the following technical solution:
  • a positive electrode piece, including a positive-electrode current collector and a positive-electrode active material layer coated on one or both surfaces of the positive-electrode current collector, where the positive-electrode active material layer includes a positive-electrode active material, a conductive agent and a polymer electrolyte, where the polymer electrolyte includes a polymer and a lithium salt, and the polymer includes a repeating unit as shown in Formula 1 below:
  • Figure US20230114916A1-20230413-C00001
  • in Formula 1, R1 is selected from H or C1-6 alkyl group; R2 is selected from a connecting group; R3 is selected from a capping group; M is selected from polyphenylene oxide chain segment, polyethylene glycol chain segment, polyethylene dithiol chain segment, polycarbonate chain segment, polypropylene glycol chain segment or polysiloxane chain segment.
  • According to the present disclosure, R1 is selected from H or C1-3 alkyl group; R2 is a connecting group formed by a reaction of hydroxyl group in
  • Figure US20230114916A1-20230413-C00002
  • with R3′ in
  • Figure US20230114916A1-20230413-C00003
  • R3 and R3′ are the same or different, and are each independently selected from H, OH, COOH and NH2 and cannot be H at the same time.
  • According to the present disclosure, the polyphenylene oxide chain segment has a repeating unit shown in Formula 2:
  • Figure US20230114916A1-20230413-C00004
  • in Formula 2, R4 is selected from H or C1-6 alkyl group, and m is an integer between 0-4. Exemplarily, R4 is selected from H or C1-3 alkyl group, and m is an integer between 0-2;
  • the polyethylene glycol chain segment has a repeating unit shown in Formula 3:
  • Figure US20230114916A1-20230413-C00005
  • the polypropylene glycol chain segment has a repeating unit shown in Formula 4:
  • Figure US20230114916A1-20230413-C00006
  • the polyethylene dithiol chain segment has a repeating unit shown in Formula 5:
  • Figure US20230114916A1-20230413-C00007
  • the polycarbonate chain segment has a repeating unit shown in Formula 6:
  • Figure US20230114916A1-20230413-C00008
  • and the polysiloxane chain segment has a repeating unit shown in Formula 7:
  • Figure US20230114916A1-20230413-C00009
  • According to the present disclosure, the polymer is selected from at least one of polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polyethylene dithiol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.
  • According to the present disclosure, a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
  • Figure US20230114916A1-20230413-C00010
  • in Formula 8, R1, R2, R3 and M are defined as above.
  • According to the present disclosure, the compound shown in Formula 8 is selected from at least one of polyphenylene oxide acrylate, polyethylene glycol methyl methacrylate, polycarbonate acrylate, polypropylene glycol methacrylate, poly(lithium-sulfonate) methacrylate, and polysiloxane methyl methacrylate.
  • According to the present disclosure, the positive-electrode active material layer includes the following components in mass percentage of content: 70-95 wt % of the positive-electrode active material, 2-15 wt % of the conductive agent, 3 -28 wt % of the above-mentioned polymer electrolyte and 0-10 wt % of a binder.
  • According to the present disclosure, in the polymer electrolyte, a molar ratio of other elements except carbon and hydrogen in the polymer to lithium element in the lithium salt is 5:1-25:1, such as 5:1, 10:1, 15:1, 20:1, 25:1, where the other elements except carbon and hydrogen can be, for example, oxygen, sulfur or silicon element.
  • According to the present disclosure, a porosity of the positive electrode piece is 0%-5%; and/or an elongation ratio of the positive-electrode active material layer in the positive electrode piece is 5%-500%.
  • The present disclosure further provides a solid state battery, and the solid state battery includes the positive electrode piece described above.
  • The beneficial effects of the present disclosure:
  • The present disclosure provides a positive electrode piece and a secondary battery including the positive electrode piece. The present disclosure selects a type of polymer electrolyte prepared from a polymer different from that in the prior art as the solid electrolyte in the positive electrode piece, the solid electrolyte have both a bonding function and a lithium conduction function, can replace a binder and a solid electrolyte in an existing electrode piece, can effectively improve and enhance transmission performance of the lithium ion, and reduce the internal resistance of the battery. Meanwhile, the positive electrode piece including the solid electrolyte has low porosity, below about 5%, which greatly reduces the voids and holes in the positive electrode piece, increases the content of the positive-electrode active material in unit volume, improves the transmission of lithium ions and electrons, and effectively improves the energy density, cycling performance and rate performance of the battery. The positive electrode piece including the solid electrolyte can be used in a battery system with high energy density, and broadens application field thereof.
    • DESCRIPTION OF EMBODIMENTS
  • <Positive Electrode Piece>
  • As above mentioned, the present disclosure provides a positive electrode piece, the positive electrode piece includes a positive-electrode current collector and a positive-electrode active material layer coated on one or both surfaces of the positive-electrode current collector, the positive-electrode active material layer includes a positive-electrode active material, a conductive agent and a polymer electrolyte, where the polymer electrolyte includes a polymer and a lithium salt, and the polymer includes a repeating unit as shown in Formula 1 below:
  • Figure US20230114916A1-20230413-C00011
  • in Formula 1, R1 is selected from H or C1-6 alkyl group; R2 is selected from a connecting group; R3 is selected from a capping group; M is selected from polyphenylene oxide chain segment, polyethylene glycol chain segment, polyethylene dithiol chain segment , polycarbonate chain segment, polypropylene glycol chain segment or polysiloxane chain segment.
  • In an embodiment of the present disclosure, R1 is selected from H or C1-3 alkyl group, for example, R1 is selected from H or methyl.
  • In an embodiment of the present disclosure, R2 is a connecting group formed by a reaction of hydroxyl group in
  • Figure US20230114916A1-20230413-C00012
    • and R3′ in
  • Figure US20230114916A1-20230413-C00013
  • In essence, R2 is a residue of R3′, where R3′ is a capping group of M.
  • In an embodiment of the present disclosure, R3 and R3′ are the same or different, and are each independently selected from H, OH, COOH, NH2 and other capping group that can react with hydroxyl group, and cannot be H at the same time.
  • In an embodiment of the present disclosure, the polyphenylene oxide chain segment has a repeating unit shown in Formula 2:
  • Figure US20230114916A1-20230413-C00014
  • in Formula 2, R4 is selected from H or C1-6 alkyl group, and m is an integer between 0-4. Exemplarily, R4 is selected from H or C1-3 alkyl group, and m is an integer between 0-2; specifically, the polyphenylene oxide chain segment has a repeating unit shown in Formula 2′:
  • Figure US20230114916A1-20230413-C00015
  • In an embodiment of the present disclosure, the polyethylene glycol chain segment has a repeating unit shown in Formula 3:
  • Figure US20230114916A1-20230413-C00016
  • In an embodiment of the present disclosure, the polypropylene glycol chain segment has a repeating unit shown in Formula 4:
  • Figure US20230114916A1-20230413-C00017
  • In an embodiment of the present disclosure, the polyethylene dithiol chain segment has a repeating unit shown in Formula 5:
  • Figure US20230114916A1-20230413-C00018
  • In an embodiment of the present disclosure, the polycarbonate chain segment has a repeating unit shown in Formula 6:
  • Figure US20230114916A1-20230413-C00019
  • In an embodiment of the present disclosure, the polysiloxane chain segment has a repeating unit shown in Formula 7:
  • Figure US20230114916A1-20230413-C00020
  • In an embodiment of the present disclosure, a number average molecular weight of M is 200-40000.
  • In an embodiment of the present disclosure, the polymer is selected from at least one of polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polyethylene dithiol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.
  • In an embodiment of the present disclosure, a number average molecular weight of the polymer is 1000-300000, preferably 10000-200000.
  • In an embodiment of the present disclosure, a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
  • Figure US20230114916A1-20230413-C00021
  • in Formula 8, R1, R2, R3 and M are defined as above.
  • In an embodiment of the present disclosure, the compound shown in Formula 8 is selected from at least one of polyphenylene oxide acrylate, polyethylene glycol methyl methacrylate, polycarbonate acrylate, polypropylene glycol methacrylate, poly(lithium-sulfonate) methacrylate, and polysiloxane methyl methacrylate.
  • In an embodiment of the present disclosure, the positive-electrode active material layer includes the following components in mass percentage of content: 70-95 wt % of positive-electrode active material, 2-15 wt % of conductive agent, 3-28 wt % of the above-mentioned polymer electrolyte and 0-10 wt % of binder.
  • In an embodiment of the present disclosure, in the polymer electrolyte, a molar ratio of other elements except carbon and hydrogen in the polymer to lithium element in the lithium salt is 5:1-25:1, such as 5:1, 10:1, 15:1, 20:1, or 25:1, where the other elements except carbon and hydrogen can be, for example, oxygen, sulfur or silicon element.
  • Exemplarily, a content of the positive-electrode active material in mass percentage is 70 wt %, 71 wt %, 72 wt %, 73 wt %, 74 wt %, 75 wt %, 76 wt %, 77 wt %, 78 wt %, 79 wt %, 80 wt %, 81 wt %, 82 wt %, 83 wt %, 84 wt %, 85 wt %, 86 wt %, 87 wt %, 88 wt %, 89 wt %, 90 wt %, 91 wt %, 92 wt %, 93 wt %, 94 wt %, or 95 wt %.
  • Exemplarily, a content of the conductive agent in mass percentage is 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, or 15 wt %.
  • Exemplarily, a content of the polymer electrolyte in mass percentage is 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, 15 wt %, 16 wt %, 17 wt %, 18 wt %, 19 wt %, 20 wt %, 21 wt %, 22 wt %, 23 wt %, 24 wt %, 25 wt %, 26 wt %, 27 wt %, or 28 wt %.
  • Exemplarily, a content of the binder in mass percentage is 0 wt %, 1 wt %, 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, or 10 wt %.
  • In an embodiment of the present disclosure, the positive-electrode active material is selected from one of or a combination of more of ferrous lithium phosphate (LiFePO4), lithium cobaltate (LiCoO2), lithium nickel cobalt manganate (LizNixCoyMn1-x-yO2, where 0.95≤z≤1.05, x>0, y>0, 0<x+y<1), lithium manganate (LiMnO2), lithium nickel cobalt aluminate (LizNixCoyAl1-x-yO2, where 0.95≤z≤1.05, x>0, y>0, 0.8≤x+y<1), lithium nickel cobalt manganese aluminate (LizNixCoyMnwAl1-x-y-wO2, where 0.95≤z≤1.05, x>0, y>0, w>0, 0.8≤x+y+w<1), nickel cobalt aluminum tungsten material, lithium-rich manganese-based solid solution positive-electrode material (xLi2MnO3.(1−x) LiMO2, where M=Ni/Co/Mn), lithium nickel cobaltate (LiNixCoyO2, where x>0, y>0, x+y=1), lithium nickel titanium magnesate (LiNixTiyMgzO2, where x>0, y>0, z>0, x+y+z=1), lithium nickelate (Li2NiO2), spinel lithium manganate (LiMn2O4), and nickel cobalt tungsten materials.
  • In an embodiment of the present disclosure, the lithium salt is selected from one of lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate (LiAsF6), lithium tetrafluoroborate (LiBF4), lithium bisoxalate borate (LiBOB), lithium difluorooxalate borate (LiDFOB), lithium bis(difluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulphonyl)imide (LiTFSI), lithium trifluoromethylsulfonate (LiCF3SO3), lithium bismalonate borate (LiBMB), lithium malonate oxalate borate (LiMOB), lithium hexafluoroantimonate (LiSbF6), lithium difluorophosphate (LiPO2F2), lithium 4,5 -dicyano-2-trifluoromethylimidazole (LiDTI), lithium bis(trifluoromethylsulfonyl)imine (LiN(SO2CF3)2), LiN(SO2C2F5)2, LiC(SO2CF3)3, and LiN(SO2F)2, or any combination thereof.
  • In an embodiment of the present disclosure, the conductive agent is selected from one or more of conductive carbon black, Ketjen black, conductive fiber, conductive polymer, acetylene black, carbon nanotube, graphene, flake graphite, conductive oxide and metal particle.
  • In an embodiment of the present disclosure, the binder is selected from at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinylidene fluoride hexafluoropropylene and poly(lithium-acrylate) (PAALi).
  • In one embodiment of the present disclosure, the positive electrode piece is used in a solid state battery (such as an all-solid state battery).
  • In an embodiment of the present disclosure, a porosity of the positive electrode piece is 0%-5%.
  • In an embodiment of the present disclosure, an elongation ratio of the positive-electrode active material layer in the positive electrode piece is 5%-500%.
  • In an embodiment of the present disclosure, a surface density of the positive electrode piece is 5-30 mg/cm2.
  • The present disclosure also provides a preparation method of the positive electrode piece, which includes the following steps: uniformly mixing a solvent, a positive-electrode active material, a conductive agent, a polymer monomer shown in Formula 8, an initiator and a lithium salt to prepare a positive electrode slurry; coating the positive electrode slurry on a surface of a positive-electrode current collector, and drying and hot pressing, to obtain the positive electrode piece.
  • In an embodiment of the present disclosure, the positive electrode slurry includes 200-1000 parts of the solvent, 70-95 parts of the positive-electrode active material, 2-15 parts of the conductive agent, 3-28 parts of the polymer monomer shown in Formula 8, the initiator and the lithium salt, and 0-10 parts of a binder; where a molar ratio of other elements except carbon and hydrogen in the polymer monomer shown in Formula 8 to lithium element in the lithium salt is 5:1-25:1, and an addition amount of the initiator is 0.05-1 wt % of the mass of the polymer monomer shown in Formula 8.
  • In an embodiment of the present disclosure, the initiator can be one or more of azodiisobutyronitrile, azodiisoheptonitrile, dimethyl azodiisobutyrate, benzoyl peroxide, tert-butyl peroxybenzoate, 4-(N,N-dimethylamino)ethyl benzoate, methyl o-benzoylbenzoate, and the like.
  • In an embodiment of the present disclosure, the solvent is selected from at least one of N-methylpyrrolidone, acetonitrile, hydrofluoroether, acetone, tetrahydrofuran, dichloromethane, pyridine, xylene and toluene.
  • In an embodiment of the present disclosure, the positive electrode slurry is preferably sieved positive electrode slurry, such as through a 200-mesh sieve.
  • In an embodiment of the present disclosure, a temperature of the drying is 60° C.-120° C., and time of the drying is 6-36 hours; further preferably, the drying is carried out under vacuum.
  • In an embodiment of the present disclosure, a temperature of the hot pressing is 50° C.-90° C., and time of the hot pressing is 5-60 minutes.
  • It was found through research that in the present disclosure, the positive-electrode active material, the conductive agent, optionally the binder, the polymer monomer, the initiator and the lithium salt are dissolved in the solvent, uniformly mixed, and coated on the surface of the current collector, and then is dried, hot pressed, and then the positive electrode piece of the present disclosure is obtained.
  • In the positive electrode slurry, the polymer monomer, due to its small molecular weight and short polymer chain segment, can be fully mixed with the positive-electrode active material, the conductive agent, optionally the binder and the lithium salt. After the solvent is removed, a highly efficient lithium conductive network has been formed in the positive-electrode active material layer, and is subjected to hot pressing under vacuum. On the one hand, the hot pressing is to initiate thermal polymerization of the polymer monomer, the polymer monomer is viscous liquid, semi-solid or solid at room temperature, and the polymer monomer becomes a flowable liquid at high temperature, can fully immerse into the internal voids of the electrode piece, and conducts thermal initiation polymerization in the voids, where the thermal initiation polymerization process (time and temperature) is adjustable to ensure the lithium conductivity of the positive electrode piece; on the other hand, the hot pressing polymer process under vacuum is adopted, the vacuum can remove air between particles inside the electrode piece, and the hot pressing can ensure compaction of the electrode piece, to be closer to the practical application. The above processes are mainly to ensure performance of the electrode piece with low void ratio, high lithium conductivity and high conductivity.
  • The present disclosure also provides a solid state battery, and the solid state battery includes the positive electrode piece described above.
  • The present disclosure also provides an electrical device, and the electrical device includes the positive electrode piece described above.
  • In an embodiment of the present disclosure, the electrical device is a digital appliance, a power tool, an energy storage device, an unmanned aerial vehicle, a household appliance, an energy storage product, an electric vehicle, an electric tool, and the like.
  • The present disclosure will be further described in detail below in combination with specific examples. It should be understood that the following examples are only to illustrate and explain the present disclosure, and should not be interpreted as a limitation on the scope of protection of the present disclosure. All technologies realized based on the above contents of the present disclosure are covered in the scope of protection of the present disclosure.
  • Unless otherwise specified, the experimental methods used in the following examples are conventional methods; and reagents, materials, and the like used in the following examples can be obtained from commercial sources unless otherwise specified.
    • EXAMPLE 1
  • 1) Preparation of Positive Electrode Piece:
  • 92 g of lithium cobaltate as positive-electrode active material , 3 g of polyphenylene oxide acrylate, 0.33 g of LiBF4, 0.67 g of LiTFSI, 1 g of polyvinylidene fluoride (PVDF) as binder, 1 g of carbon black as conductive agent, 1 g of carbon nanotube as conductive agent, 0.01 g of azodiisobutyronitrile were mixed, 1000 g of N-methylpyrrolidone (NMP) was added, and stirred under the action of a vacuum mixer until the mixed system becomes a uniform flowable positive electrode slurry; the positive electrode slurry was applied evenly on an aluminum foil with a thickness of 10 μm; after drying at 60° C. for 36 hours, the electrode piece was obtained after vacuumization treatment, and the electrode piece was hot pressed at 50° C. for 60 minutes, and then cut to obtain the positive electrode piece.
  • 2) Preparation of Negative Electrode Piece:
  • 5 g of SiOx (0<x<2), 10 g of lithium metal powder, 3 g of conductive carbon black as conductive agent, and 1 g of oil based acrylate as binder were dissolved in 50 g of xylene, mixed evenly, and coated on a surface of a copper foil for a negative-electrode current collector, and then dried (temperature: 85° C., time: 5 h, argon gas), rolled and die cut, to obtain the negative electrode piece.
  • 3) Preparation of Solid Electrolyte Film:
  • 100 g of polyethylene oxide, 20 g of LiTFSI and 1000 g of acetonitrile were added into a reactor, stirred at a speed of 500 r/min, and stirred for 24 h under protection of inert gas, and then the slurry obtained was coated on a flat polytetrafluoroethylene plate, and the solid electrolyte film was obtained by removing the solvent.
  • 4) Preparation Of Lithium-Ion Battery:
  • the positive electrode piece, the solid electrolyte film and the negative electrode piece obtained above were laminated to prepare a solid lithium-ion battery cell, which was welded and encapsulated, to obtain the lithium-ion battery.
    • Comparative Example 1-1
  • A specific process may refer to Example 1, where a main difference is that in the Comparative example 1-1, polyphenylene oxide is used to replace the polyphenylene oxide acrylate in Example 1; and other conditions are consistent with Example 1.
    • Comparative Example 1-2
  • A specific process may refer to Example 1, where a main difference is that a mixture of polyphenylene oxide and polyacrylate with the same mass as the polyphenylene oxide acrylate monomer is used in the Comparative example 1-2 to replace the polyphenylene oxide acrylate in Example 1, where a mass ratio of polyphenylene oxide and polyacrylate is a molecular weight ratio of polyphenylene oxide to acrylate in the polyphenylene oxide acrylate monomer; and other conditions are consistent with Example 1.
    • Other Examples and Other Comparative Examples
  • Specific processes may refer to Example 1, where main differences are the process conditions, addition amounts of respective components, and types of respective component materials. See Table 1 and Table 2 for details. Among them, Examples 1-6 in Table 1 further include 0.01 g of initiators, all of which are azodiisobutyronitrile. In the comparative examples in Table 2 where two polymers are added, addition amounts of the two polymers are a molecular weight ratio of the polymer chain segments to the poly(meth)acrylate in the polymer monomers added in corresponding examples. See description of the above Comparative example 1-2 for details.
  • TABLE 1
    Positive- Polymer Hot Hot
    electrode Con- or Drying Drying pressing pressing
    active ductive monomer Lithium temperature time temperature time
    No. Solvent/g material/g agent/g thereof/g salt/g Binder/g (° C.) (h) (° C.) (min)
    Example 1 1000 92 2  3 2  1  60 36 50 60
    Comparative 1000 92 2  3 2  1  60 36 50 60
    example 1-1
    Comparative 1000 92 2  3 2  1  60 36 50 60
    example 1-2
    Example 2  600 75 8 12 5  0  90 24 65 10
    Comparative  600 75 8 12 5  0  90 24 65 10
    example 2-1
    Comparative  600 75 8 12 5  0  90 24 65 10
    example 2-2
    Example 3  400 70 5 12 3 10 120  6 80 15
    Comparative  400 70 5 12 3 10 120  6 80 15
    example 3-1
    Comparative  400 70 5 12 3 10 120  6 80 15
    example 3-2
    Example 4  500 90 3  6 1  0 110 16 90  5
    Comparative  500 90 3  6 1  0 110 16 90  5
    example 4-1
    Comparative  500 90 3  6 1  0 110 16 90  5
    example 4-2
    Example 5  800 80 6 10 4  0 100  8 75 30
    Comparative  800 80 6 10 4  0 100  8 75 30
    example 5-1
    Comparative  800 80 6 10 4  0 100  8 75 30
    example 5-2
    Example 6  200 70 8 12 8  2  80 30 55 35
    Comparative  200 70 8 12 8  2  80 30 55 35
    example 6-1
    Comparative  200 70 8 12 8  2  80 30 55 35
    example 6-2
  • TABLE 2
    Positive-
    electrode
    active Conductive
    No. Solvent material agent Polymer monomer/polymer Binder Lithium salt
    Example 1 NMP Lithium Conductive Polyphenylene oxide acrylate (molecular PVDF LiBF4:LiTFSI
    cobaltate carbon black: weight of monomer 400; molecular weight of (1:2)
    carbon polymer 20000)
    Comparative nanotube Polyphenylene oxide
    example 1-1 (1:1) (molecular weight 20000)
    Comparative Polyphenylene oxide (molecular weight 20000) +
    example 1-2 polyacrylate (molecular weight 20000)
    Example 2 Ace- Ferrous Conductive Polyethylene glycol methyl methacrylate None LiFSI:LiTFSI
    tonitrile lithium carbon black: (molecular weight of monomer 950; molecular (1:3)
    phosphate Ketjen black weight of polymer 100000)
    Comparative (2:1) Polypropylene glycol (molecular weight
    example 2-1 100000)
    Comparative Polypropylene glycol (molecular weight
    example 2-2 100000) + polymethacrylate (molecular weight
    100000)
    Example 3 DMF Lithium-rich Conductive Polycarbonate acrylate (molecular weight of PVDF LiBF4:LiFSI
    manganese- fiber:carbon monomer 1500; molecular weight of (3:1)
    based material nanotube polymer150000)
    Comparative (1:1) Polycarbonate
    example 3-1 (molecular weight 150000)
    Comparative Polycarbonate (molecular weight 150000) +
    example 3-2 polyacrylate (molecular weight 150000)
    Example 4 Acetone Nickel cobalt Carbon Polyethylene glycol methyl methacrylate None LiBOB:
    manganese nanotube: (molecular weight of monomer 300; molecular LiTFSI
    ternary graphene weight of polymer100000) (1:4)
    Comparative material (1:2) Polypropylene glycol
    example 4-1 (molecular weight:10000)
    Comparative Polypropylene glycol (molecular weight:
    example 4-2 10000) + polymethacrylate (molecular weight:
    10000)
    Example 5 DMF Nickel cobalt Conductive Polypropylene glycol methacrylate (molecular None LiFSI:
    aluminum carbon black: weight of monomer 1000; molecular weight of LiTFSI
    ternary carbon polymer 50000) (1:2)
    Comparative material nanotube Polypropylene glycol
    example 5-1 (2:1) (molecular weight 50000)
    Comparative Polypropylene glycol (molecular weight
    example 5-2 50000) + polymethacrylate
    (molecular weight 50000)
    Example 6 NMP Nickel cobalt Carbon polysiloxane methyl methacrylate (molecular PVDF LiBF4:
    manganese nanotube: weight of monomer 400; molecular weight of LiBOB:
    ternary flake graphite polymer 200000) LiTFSI
    Comparative material (3:1) Polysiloxane (molecular weight 200000) (1:2:3)
    example 6-1
    Comparative Polysiloxane (molecular weight 200000) +
    example 6-2 polymethacrylate (molecular weight 200000)
  • Performance Test:
  • Test method for battery internal resistance alternating current impedance: alternating current impedance for lithium-ion battery is tested in 100 KHz-0.1 mHz range at 60° C., using Metrohm PGSTAT302N chemical workstation.
  • Test method for porosity of electrode piece: porosity of electrode piece is tested using mercury porosimeter with model 9610 under AutoPore V series, where a certain electrode piece is taken and placed in a dilatometer, which is coated with high-pressure sealing oil, covered and sealed with threads, and then placed in a high-pressure system to test the porosity of electrode piece under high pressure.
  • Test method for elongation ratio of electrode piece: positive electrode slurry is coated on a smooth and flat surface, dried and hot pressed, to obtain a slurry-coated layer, which is prepared to 60 mm*20 mm*1 mm (length*width*thickness) sample, and a tensile test is conducted on the sample on hydraulic universal material testing machine with model GH-969C.
  • Test method for battery cycling performance: a charge and discharge cycling test for a lithium-ion battery is conducted on a battery (from LANHE) charge and discharge test cabinet, with the test conditions being 60° C., 0.3 C/0.3 C charge and discharge, and cycling times when battery capacity retention rate drops to 80% are investigated.
  • Test method for battery cycling rate performance: a charge and discharge cycling test for a lithium-ion battery is conducted on a battery (from LANHE) charge and discharge test cabinet, with the test conditions being 60° C., and a process at 0.3 C/0.3 C (5 cycles)→0.5 C/0.5 C (5 cycles)→1 C/1 C (5 cycles)→2 C/2 C (5 cycles)→0.3 C/0.3 C (5 cycles) is carried out.
  • TABLE 3
    Internal resistance of batteries, porosity of positive electrode
    pieces, and elongation ratio of positive-electrode active
    material layers in Examples and Comparative examples
    Porosity Elongation ratio Internal resistance
    No. (%) (%) (mΩ)
    Example 1 2 30 120
    Comparative 30 10 560
    example 1-1
    Comparative 27 5 930
    example 1-2
    Example 2 1 450 113
    Comparative 27 200 530
    example 2-1
    Comparative 25 80 895
    example 2-2
    Example 3 4 260 128
    Comparative 26 240 630
    example 3-1
    Comparative 25 50 937
    example 3-2
    Example 4 0.5 50 103
    Comparative 25 23 421
    example 4-1
    Comparative 29 6 774
    example 4-2
    Example 5 4.5 200 146
    Comparative 23 120 621
    example 5-1
    Comparative 21 70 1062
    example 5-2
    Example 6 0.8 230 153
    Comparative 24 140 624
    example 6-1
    Comparative 26 90 1085
    example 6-2
  • The porosity test results show that: in the examples, the positive electrode pieces prepared by using the compound shown in Formula 8, has low porosity; in the comparative examples, formed polymers adopted cannot achieve the effect of low porosity. A main reason is that the compound shown in Formula 8 adopted in the present disclosure is a polymer monomer, which is liquid under heat condition, and can fully contact with particles, enter voids between particles, and achieve in-situ polymerization in the voids, that is, preparing a positive electrode piece with low porosity.
  • The test results of elongation ratio show that: by comparing the elongation ratios of the positive-electrode active material layers in Examples 1-6, it can be seen that the elongation ratio of the positive-electrode active material layer is related to the amount of polymer monomer added, and the more the polymer monomer added, the better the elongation ratio; by comparing the examples with the comparative examples, the compound shown in Formula 8 in the present disclosure has obvious comb-like polymer function, where the main chain is carbon-carbon bond, and the branch chain is comb like, and the compound can effectively combine with particle materials in the positive electrode piece, has good high elasticity state, and has good elongation ratio.
  • The battery internal resistance test results show that: the compound shown in Formula 8 adopted in the examples of the present disclosure can effectively bond particles in the positive electrode piece together, and meanwhile, the polymer has a comb-like structure, and the branch chain can conduct lithium, so the positive electrode pieces prepared in Examples 1-6 have a low internal resistance. However, there is a high porosity in the comparative examples and the polyacrylate does not conduct lithium, so the positive electrode pieces prepared in the comparative examples have a high internal resistance.
  • TABLE 4
    Cycling performance and rate performance of batteries of Examples and
    Comparative examples
    Cycling
    0.3 C/0.3 C Battery capacity retention ratio after 5 cycles at different rate
    No. performance 0.3 C/0.3 C 0.3 C/0.3 C 1 C/1 C 2 C/2 C 0.3 C/0.3 C
    Example 1  860 cycles (80%) 99.93% 98.35% 95.47% 90.34% 99.70%
    Comparative  300 cycles (80%) 98.38% 96.23% 91.48% 85.85% 97.52%
    example 1-1
    Comparative  180 cycles (80%) 96.24% 92.41% 85.34% 78.93% 93.43%
    example 1-2
    Example 2 2800 cycles (80%) 99.98% 98.67% 96.35% 92.63% 99.83%
    Comparative 1500 cycles (80%) 98.56% 96.76% 91.63% 85.94% 97.93%
    example 2-1
    Comparative  650 cycles (80%) 96.47% 93.54% 85.94% 79.49% 94.62%
    example 2-2
    Example 3  360 cycles (80%) 98.89% 97.42% 92.34% 87.43% 98.21%
    Comparative  164 cycles (80%) 94.32% 92.54% 84.34% 76.37% 92.36%
    example 3-1
    Comparative  89 cycles (80%) 87.34% 84.37% 73.47% 64.95% 85.48%
    example 3-2
    Example 4 1520 cycles (80%) 99.95% 98.43% 96.14% 92.47% 99.75%
    Comparative  794 cycles (80%) 98.32% 96.48% 91.42% 85.12% 97.21%
    example 4-1
    Comparative  485 cycles (80%) 96.12% 93.11% 85.32% 79.11% 94.13%
    example 4-2
    Example 5 1629 cycles (80%) 99.96% 98.51% 96.21% 92.52% 99.81%
    Comparative  820 cycles (80%) 98.41% 96.53% 91.51% 85.81% 97.50%
    example 5-1
    Comparative  368 cycles (80%) 96.23% 93.26% 85.41% 79.32% 94.43%
    example 5-2
    Example 6 1028 cycles (80%) 99.94% 98.61% 95.62% 91.21% 99.76%
    Comparative  521 cycles (80%) 99.31% 97.13% 92.56% 87.81% 98.11%
    example 6-1
    Comparative  221 cycles (80%) 97.25% 93.49% 86.73% 79.84% 94.42%
    example 6-2
  • The results of the cycling performance tests for the examples and the comparative examples show that: the positive electrode pieces of the present disclosure have a low porosity and a small internal resistance, which makes that the batteries prepared have an advantage in cycling performance; however, the positive electrode pieces in the comparative examples have a high porosity and a high internal resistance, leading to a significant reduction of the effective cycling times of the batteries.
  • The results of the charge-discharge rate performance test for the examples and the comparative examples show that: the positive electrode pieces of the present disclosure have a low porosity and a small internal resistance, and the lithium ions have good lithium conductive channels in the positive electrode pieces, which makes that the prepared lithium-ion batteries have good rate performance and good application value.
  • The embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above embodiments. Any modification, equivalent replacement, improvement, and the like made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims (20)

What is claimed is:
1. A positive electrode piece, wherein the positive electrode piece comprises a positive-electrode current collector and a positive-electrode active material layer coated on one or both surfaces of the positive-electrode current collector, the positive-electrode active material layer comprises a positive-electrode active material, a conductive agent and a polymer electrolyte, wherein the polymer electrolyte comprises a polymer and a lithium salt, and the polymer comprises a repeating unit as shown in Formula 1 below:
Figure US20230114916A1-20230413-C00022
in Formula 1, R1 is selected from H or C1-6 alkyl group; R2 is selected from a connecting group; R3 is selected from a capping group; M is selected from polyphenylene oxide chain segment, polyethylene glycol chain segment, polyethylene dithiol chain segment, polycarbonate chain segment, polypropylene glycol chain segment or polysiloxane chain segment.
2. The positive electrode piece according to claim 1, wherein R1 is selected from H or C1-3 alkyl group; R2 is a connecting group formed by a reaction of hydroxyl group in
Figure US20230114916A1-20230413-C00023
and R3′ in
Figure US20230114916A1-20230413-C00024
R3 and R3′ are same or different, and are each independently selected from H, OH, COOH and NH2 and are not H at the same time.
3. The positive electrode piece according to claim 1, wherein the polyphenylene oxide chain segment has a repeating unit shown in Formula 2:
Figure US20230114916A1-20230413-C00025
in Formula 2, R4 is selected from H or C1-6 alkyl group, and m is an integer between 0-4;
the polyethylene glycol chain segment has a repeating unit shown in Formula 3:
Figure US20230114916A1-20230413-C00026
the polypropylene glycol chain segment has a repeating unit shown in Formula 4:
Figure US20230114916A1-20230413-C00027
the polyethylene dithiol chain segment has a repeating unit shown in Formula 5:
Figure US20230114916A1-20230413-C00028
the polycarbonate chain segment has a repeating unit shown in Formula 6:
Figure US20230114916A1-20230413-C00029
and
the polysiloxane chain segment has a repeating unit shown in Formula 7:
Figure US20230114916A1-20230413-C00030
4. The positive electrode piece according to claim 3, wherein R4 is selected from H or C1-3 alkyl group, and m is an integer between 0-2.
5. The positive electrode piece according to claim 2, wherein the polyphenylene oxide chain segment has a repeating unit shown in Formula 2:
Figure US20230114916A1-20230413-C00031
in Formula 2, R4 is selected from H or C1-6 alkyl group, and m is an integer between 0-4;
the polyethylene glycol chain segment has a repeating unit shown in Formula 3:
Figure US20230114916A1-20230413-C00032
the polypropylene glycol chain segment has a repeating unit shown in Formula 4:
Figure US20230114916A1-20230413-C00033
the polyethylene dithiol chain segment has a repeating unit shown in Formula 5:
Figure US20230114916A1-20230413-C00034
the polycarbonate chain segment has a repeating unit shown in Formula 6:
Figure US20230114916A1-20230413-C00035
and
the polysiloxane chain segment has a repeating unit shown in Formula 7:
Figure US20230114916A1-20230413-C00036
6. The positive electrode piece according to claim 5, wherein R4 is selected from H or C1-3 alkyl group, and m is an integer between 0-2.
7. The positive electrode piece according to claim 1, wherein the polymer is selected from at least one of polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polyethylene dithiol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.
8. The positive electrode piece according to claim 2, wherein the polymer is selected from at least one of polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polyethylene dithiol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.
9. The positive electrode piece according to claim 3, wherein the polymer is selected from at least one of polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polyethylene dithiol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.
10. The positive electrode piece according to claim 5, wherein the polymer is selected from at least one of polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polyethylene dithiol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.
11. The positive electrode piece according to claim 1, wherein a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
Figure US20230114916A1-20230413-C00037
in Formula 8, R1, R2, R3 and M are defined as above.
12. The positive electrode piece according to claim 2, wherein a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
Figure US20230114916A1-20230413-C00038
in Formula 8, R1, R2, R3 and M are defined as above.
13. The positive electrode piece according to claim 3, wherein a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
Figure US20230114916A1-20230413-C00039
in Formula 8, R1, R2, R3 and M are defined as above.
14. The positive electrode piece according to claim 5, wherein a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
Figure US20230114916A1-20230413-C00040
in Formula 8, R1, R2, R3 and M are defined as above.
15. The positive electrode piece according to claim 7, wherein a monomer for preparing the polymer is selected from a compound shown in Formula 8 below:
Figure US20230114916A1-20230413-C00041
in Formula 8, R1, R2, R3 and M are defined as above.
16. The positive electrode piece according to claim 11, wherein the compound shown in Formula 8 is selected from at least one of polyphenylene oxide acrylate, polyethylene glycol methyl methacrylate, polycarbonate acrylate, polypropylene glycol methacrylate, poly(lithium-sulfonate) methacrylate, and polysiloxane methyl methacrylate.
17. The positive electrode piece according to claim 1, wherein the positive-electrode active material layer comprises the following components in mass percentages of content: 70-95 wt % of the positive-electrode active material, 2-15 wt % of the conductive agent, 3-28 wt % of the polymer electrolyte and 0-10 wt % of a binder.
18. The positive electrode piece according to claim 1, wherein in the polymer electrolyte, a molar ratio of other elements except carbon and hydrogen in the polymer to lithium element in the lithium salt is 5:1-25:1.
19. The positive electrode piece according to claim 1, wherein a porosity of the positive electrode piece is 0%-5%; and/or an elongation ratio of the positive-electrode active material layer in the positive electrode piece is 5%-500%.
20. A solid state battery, comprising the positive electrode piece according to claim 1.
US18/065,616 2020-06-29 2022-12-13 Positive electrode piece and secondary battery including same Pending US20230114916A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CN202010606376.2A CN113937288B (en) 2020-06-29 2020-06-29 Positive pole piece and secondary battery containing same
CN202010606376.2 2020-06-29
PCT/CN2021/094181 WO2022001429A1 (en) 2020-06-29 2021-05-17 Positive electrode plate and secondary battery comprising same

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/094181 Continuation WO2022001429A1 (en) 2020-06-29 2021-05-17 Positive electrode plate and secondary battery comprising same

Publications (1)

Publication Number Publication Date
US20230114916A1 true US20230114916A1 (en) 2023-04-13

Family

ID=79273118

Family Applications (1)

Application Number Title Priority Date Filing Date
US18/065,616 Pending US20230114916A1 (en) 2020-06-29 2022-12-13 Positive electrode piece and secondary battery including same

Country Status (3)

Country Link
US (1) US20230114916A1 (en)
CN (1) CN113937288B (en)
WO (1) WO2022001429A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118489169A (en) * 2022-09-15 2024-08-13 宁德时代新能源科技股份有限公司 Polymer, positive electrode material composition and application thereof

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003268053A (en) * 2002-03-13 2003-09-25 Hitachi Chem Co Ltd Binder resin for battery and electrode and battery comprising the same
JP5085856B2 (en) * 2005-07-07 2012-11-28 パナソニック株式会社 Lithium ion secondary battery
JP5290699B2 (en) * 2008-10-22 2013-09-18 シャープ株式会社 Lithium secondary battery
CN103682433A (en) * 2012-09-26 2014-03-26 中国科学院研究生院 Multi-arm star-shaped block polymer based electrolyte and preparation method thereof
CA3020192A1 (en) * 2016-04-22 2017-10-26 Hydro-Quebec Copolymer binder
CN109216650B (en) * 2017-06-30 2021-04-20 比亚迪股份有限公司 Battery electrode, preparation method thereof and all-solid-state battery
CN107591536B (en) * 2017-09-02 2020-08-11 清陶（昆山）能源发展有限公司 Gel composite positive plate, preparation method thereof and method for preparing all-solid-state lithium battery
CN110943249B (en) * 2018-09-25 2021-06-18 深圳市比亚迪锂电池有限公司 Polymer electrolyte and lithium ion battery
CN110003399A (en) * 2019-03-06 2019-07-12 南开大学 A kind of preparation and application of single ion conductive polymer electrolyte film
CN110137497B (en) * 2019-05-11 2021-05-25 珠海冠宇电池股份有限公司 Negative electrode binder, preparation method thereof and lithium ion battery

Also Published As

Publication number Publication date
CN113937288A (en) 2022-01-14
CN113937288B (en) 2023-04-18
WO2022001429A1 (en) 2022-01-06

Similar Documents

Publication Publication Date Title
EP2162936B1 (en) Anode material of excellent conductivity and high power secondary battery employed with the same
CN101276895B (en) Composition for lithium ion secondary battery porous diaphragm layer and lithium ion secondary battery
US9413011B2 (en) Binder for secondary battery exhibiting excellent adhesion force
US20100129704A1 (en) Silicon Negative Electrode, Lithium Ion Battery, Method of Preparing the Same
CN110061286B (en) High-energy-density lithium ion battery with pre-lithiation effect and preparation method thereof
US20050158624A1 (en) Anode for lithium secondary battery and lithium secondary battery using the anode
CN110785886A (en) Lithium secondary battery
US8927152B2 (en) Binder for electrode of lithium rechargeable battery and electrode for rechargeable battery comprising the same
US20240178453A1 (en) Lithium-ion battery
CN109119631B (en) Secondary battery
WO2020243948A1 (en) In-situ polymerized polymer electrolyte for lithium ion batteries
CN112563563A (en) Composite solid electrolyte, solid battery and preparation method thereof
US20230114529A1 (en) Negative electrode piece and secondary battery including same
JP2018116831A (en) Manufacturing method of battery
US20230114916A1 (en) Positive electrode piece and secondary battery including same
WO2021163872A1 (en) In-situ polymerized hybrid polymer electrolyte for high voltage lithium batteries
CN113937250B (en) Positive pole piece and solid-state battery containing same
CN111433965A (en) Electrolyte for lithium secondary battery and lithium secondary battery comprising the same
CN110661028B (en) Lithium ion battery non-aqueous electrolyte and lithium ion battery
US20230129009A1 (en) Positive electrode plate and lithium-ion secondary battery
CN111406335A (en) Electrode for lithium secondary battery and lithium secondary battery comprising the same
WO2024113081A1 (en) Binder, electrode sheet, secondary battery, and electrical apparatus
JP7118479B2 (en) Electrolyte for lithium secondary battery and lithium secondary battery containing the same
CN115663284A (en) Electrolyte and lithium ion battery
CN117136452A (en) Lithium secondary battery with transition metal elution suppressed

Legal Events

Date Code Title Description
AS Assignment

Owner name: ZHUHAI COSMX BATTERY CO., LTD., CHINA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TANG, WEICHAO;LI, SULI;ZHAO, WEI;AND OTHERS;REEL/FRAME:062090/0865

Effective date: 20221124

STPP Information on status: patent application and granting procedure in general

Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION